ONORM EN 1488 : 2000

Materials, dimensions and performance requirements (including methods of test) for expansion groups, of nominal sizes from DN 15 to DN 40, having working pressures from 0,1 MPa (1 bar) to 1,0 MPa (10bar) are defined. Expansion groups are intended for fitting to the cold water supply of storage water heaters, having a maximum distribution temperature of 95 deg C for all energy sources. Expansion groups do not control temperature and alone do not constitute the protection required for storage water heaters. Expansion groups limit pressure, in the water heater to which they are fitted, that is produced by thermal expansion of the water.